Longitudinal changes of circumpapillary retinal nerve fiber layer thickness profile during childhood myopia progression

The purpose of this study was to evaluate longitudinal changes of circumpapillary retinal nerve fiber layer thickness (cpRNFLT) profile arising in the course of childhood myopia progression. Thirty-six eyes of 36 healthy children who showed myopia progression (spherical equivalent [SE] decrease of ≥ 2.0 diopters [D]) were included. To account for the axial-elongation-induced magnification effect on spectral-domain optical coherence tomography (SD-OCT) measurements, we calculated the proportion of quadrant-cpRNFLT distribution (i.e., the percentage of cpRNFLT within a single quadrant of total cpRNFLT). During 4.1 ± 1.1 years, the mean SE changed from -1.3 ± 0.9 to -4.3 ± 0.8D, and both the optic disc tilt ratio and the torsional angle increased (both P < 0.001). In the temporal quadrant, the cpRNFLT proportion was increased from 19.2 ± 1.86 to 24.4 ± 2.30% (P < 0.001). The cpRNFLT proportion in 3 quadrants (i.e., superior, inferior, nasal) showed decreases (all P < 0.001). Between baseline and follow up, the scan-circle location as determined by OCT was shifted mostly (94%; 34 of 36 eyes) toward the nasal side of the optic disc. With scan-circle repositioning to match the baseline, cpRNFLT distribution proportions did not show any significant difference between the baseline and follow up (all P > 0.05). For longitudinal evaluations of patients with myopia progression, scan-circle alteration should be given due consideration.